Personal portable instruments may construct a low-rate wireless personal area network (hereinafter, referred to as an LR-WPAN) to perform communication.
An example of the LR-WPAN includes a network based on an IEEE 802.15.4 standard. The IEEE 802.15.4 standard uses binary phase-shift keying (BPSK) in a band of 868/915 MHz to provide a transmission rate of 20 Kbps and 40 Kbps. In a band of 2.45 GHz, the IEEE 802.15.4 standard uses offset quadrature phase-shift keying (O-QPSK) to provide a transmission rate of 250 Kbps. An IEEE 802.15.4b standard uses O-QPSK even in a band of 868/915 MHz to provide a transmission rate of 250 Kbps.